I need help resolving a double NAT issue that I have in my current infrastructure. My current configuration has been working and doing what I need it to do for over a year now, but I have always felt there was a more efficient way to accomplish my goal. I'm no expert on routing or firewalling by any stretch of the imagination. None of my clients use or need this type of infrastructure so my only experience is with my own, very small, setup. I have a Cisco 2811 and a PIX 525 that I have always been able to get to do what I need, but again, I'm no expert.
I have AT&T U-Verse Business with a block of 5 usable static IP's. I have 5 internal LAN segments that each use one of my IP's. Before I had U-Verse, I used bridge mode on the ISP's router to assign my statics to the outside interface of the PIX and segmented the LAN from there. The problem I have now is that the device that AT&T is giving it's business clients (Motorola NVG589) doesn't have a bridge mode. After much aggravation, I discovered that the NVG589 can not assign more than one IP per MAC address. I found a solution on the internet to deal with this that involved using a Cisco router and HSRP protocol to enable the NVG589 to have a single MAC address that each IP could be assigned to. I obtained the 2811 and set it up and like I said, it has worked for a long time. The only problem is the double NAT. The only way I could figure out how to make it work was to setup HSRP with 1 physical address and 4 addresses using HSRP on the WAN interface of the 2811 and then NAT them to a new /29 address block on the LAN interface that could then be routed to the outside interface of the PIX.
My main question is: Is there a better way to accomplish the same effect without using NAT on the 2811?
I'm describing this the best way I can for being a relative novice on the subject. I have included scrubbed versions of the 2811 and PIX configs below that will hopefully clear it up for you guys.
version 12.4 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname R1 ! boot-start-marker boot-end-marker ! no aaa new-model ! resource policy ! clock timezone EST -5 clock summer-time EDT recurring ip subnet-zero ! ! ip cef ! ! ip domain name XXXXXXXX ! ! ! ! interface FastEthernet0/0 ip address XXX.XXX.XXX.5 255.255.255.248 ip nat outside duplex auto speed auto standby timers 254 255 standby preempt standby 1 ip XXX.XXX.XXX.1 standby 1 mac-address 0000.0000.0001 standby 2 ip XXX.XXX.XXX.2 standby 2 mac-address 0000.0000.0002 standby 3 ip XXX.XXX.XXX.3 standby 3 mac-address 0000.0000.0003 standby 4 ip XXX.XXX.XXX.4 standby 4 mac-address 0000.0000.0004 ! interface FastEthernet0/1 ip address 10.0.0.6 255.255.255.248 ip nat inside duplex full speed auto no mop enabled ! ip default-gateway XXX.XXX.XXX.6 ip classless ip route 0.0.0.0 0.0.0.0 XXX.XXX.XXX.6 ! no ip http server ip nat inside source list acl-inet interface FastEthernet0/0 overload ip nat inside source static 10.0.0.1 XXX.XXX.XXX.1 ip nat inside source static 10.0.0.2 XXX.XXX.XXX.2 ip nat inside source static 10.0.0.3 XXX.XXX.XXX.3 ip nat inside source static 10.0.0.4 XXX.XXX.XXX.4 ip nat inside source static 10.0.0.5 XXX.XXX.XXX.5 ! ip access-list standard acl-inet permit 10.0.0.0 0.0.0.7 ! ! control-plane ! ! line con 0 line aux 0 line vty 0 4 ! scheduler allocate 20000 1000 ! end
Question We run asr9001 with XR 6.1.3, and we have a very long delay to
login w/ SSH 1 or 2 to the device compare to IOS device. After
investigation, the there is 1s delay between the client KEXDH_INIT and
the server (XR) KEXDH_REPLY. After debug ssh serv...
Introduction The purpose of this document is to demonstrate the Open
Shortest Path First (OSPF) behavior when the V-bit (Virtual-link bit) is
present in a non-backbone area. The V-bit is signaled in Type-1 LSA only
if the router is the endpoint of one or ...
Hi, I am seeing quite a few issues with patch install and wanted to
share my experience and workaround to this. Login to admin via CLI, then
access root with the “shell” command Issue “df –h” and you’ll probably
see the following directory full or nearly ...